Abstract
BACKGROUND: Unhealthy lifestyles and multimorbidity are major determinants of adverse health outcomes in later life. However, the potential benefits of adhering to a healthy lifestyle among older people with multimorbidity remain unclear. This study aimed to evaluate the independent and joint associations of healthy lifestyle, multimorbidity, and all-cause mortality risk. METHODS: We used data from the 2005-2018 waves of the Chinese Longitudinal Healthy Longevity Survey (CLHLS), including participants aged 60 years and older. Healthy Lifestyle Index (HLI) was constructed based on five modifiable factors: body mass index (BMI), smoking status, alcohol consumption, physical activity, and dietary intake. Multimorbidity was defined as the presence of two or more chronic conditions. Cox proportional hazards regression was employed to assess the associations between healthy lifestyle, multimorbidity, and all-cause mortality, with stratified analyses by age, sex, and urban-rural residence. RESULTS: A total of 21,418 participants were included, with 15,113 deaths recorded over a median follow-up of 3.44 years (IQR 1.90-6.77). The age- and sex-adjusted mortality rate was 149.19 per 1,000 person-years (95% CI: 147.90-150.49). Among the lifestyle factors, physical activity showed the strongest association with reduced mortality (HR(d)=0.68, 95% CI 0.65-0.71; p < 0.001). Participants with a healthy lifestyle had significantly lower all-cause mortality risk compared to those with an unhealthy lifestyle (HR(d)=0.65, 95% CI 0.62-0.69; p < 0.001). Notably, the protective effect was more pronounced among those with multimorbidity (HR(c)=0.58, 95% CI 0.52-0.65; p < 0.001) than those without (HR(d)=0.65, 95% CI 0.62-0.69; p < 0.001). CONCLUSIONS: Adherence to a healthy lifestyle is associated with a significantly lower risk of all-cause mortality in older people, especially among those with multimorbidity.